Tornadoes Trends and Global Warming

It’s been a tough spring.  We’ve seen storms ravage the south from Alabama to North Carolina.  And just today, Missouri was hammered.

It’s an active storm season to be sure.  But is this just weather or is it Global Warming:

…the jet stream forces in April were among the strongest ever recorded, possibly because of La Niña conditions in the Pacific Ocean. A La Niña pattern, which leads to cooler water conditions around the Equator in the Pacific Ocean, is associated with wetter and stormier conditions through the middle of the country as cooler air from Canada surges into warm moisture heading north — made warmer, many climate scientists say, by climate change.

Ahh yes…Climate Change – Global Warming – AGW!  Of course!

It has to be Global Warming, right?

Well, maybe not.

For the storms to be attributed to global warming there would have to be a pattern, or so it would seem.  Something would have to be changing as more and more man made pollutants made their way into the atmosphere.

Maybe the number of storms?


Clearly there’s a trend.  And that trend is rending up.  It would seem that that if we are using the number of tornadoes as an indication of the impact of Global Warming, we have a good metric.



It seems that just as the number of total tornadoes is going UP we’re seeing the number of strong and violent tornadoes going ….. maybe down?

So, what can explain this?

The increase in reported tornado frequency during the early 1990s corresponds to the operational implementation of Doppler weather radars. Other nonmeteorological factors that must be considered when looking at the increase in reported tornado frequency over the past 33 years are the advent of cellular telephones; the development of spotter networks by NWS offices, local emergency management officials, and local media; and population shifts. Changnon (1982) and Schaefer and Brooks (2000) both discuss these influences on tornado reporting.

The growing “hobby” of tornado chasing has also contributed to the increasing number of reported tornadoes. The capability to easily photograph tornadoes with digital photography, camcorders, and even cell phone cameras not only provides documentation of many weak tornadoes, but also, on occasion, shows the presence of multiple tornadoes immediately adjacent to each other. (Are these individual tornadoes or manifestations of one tornado undergoing vortex breakdown?)

Perhaps there is a better way to measure tornado activity?

Dr. Changnon has long advocated the use of “event days” because of its mitigation of the impact of reporting biases (Changnon and Schnickedanz, 1969). When tornado days are plotted against year (Fig. 2), the rapid inflation that is apparent in the numbers of reported tornadoes is no longer present.

We can see the results here:

The inflation disappears.

More and more we’re seeing weather patterns being attributed to Global Warming.  More and more, we’re seeing that attribution incorrect.

4 responses to “Tornadoes Trends and Global Warming

  1. How do you explain the 504 deaths this year due to tornadoes? It is the highest since 1953. Little odd this number is so high with all the people out watching for them. Not to mention all of the technological advances in this area as well. Hmmmm…

  2. Then wouldn’t the totals go up year after year?
    Check the numbers. Beginning of 20th century, hundreds die per year. Middle of the century it drops to normally under 100 per year. This year…. over 500 ALREADY!

    • Then wouldn’t the totals go up year after year?

      Yes, we would expect those numbers to go up as the population went up; I was being snarky.

      The larger point is that we aren’t seeing any more storms now than we have for years and years. I suspect we’ve been very unlucky this year.

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